FAO reports downturn in H5N1 outbreaks for 2007

Dec 19, 2007 (CIDRAP News) – Despite recent spikes in H5N1 avian influenza activity in humans and birds, there have been fewer bird outbreaks in fewer countries this year than in 2006, according to a preliminary report from the United Nations Food and Agriculture Organization (FAO).

As of Dec 10, 30 countries had reported H5N1 cases in birds this year, compared with 54 in 2006, the FAO reported. This year five countries have reported their first outbreaks: Bangladesh, Benin, Ghana, Saudi Arabia, and Togo. Except for sporadic outbreaks in wild birds, most of the H5N1 cases this year occurred in domestic poultry, such as chickens, turkeys, geese, ducks, and quail.

The H5N1 outbreaks seemed to follow a seasonal pattern, in line with evidence that cooler temperatures are more favorable to influenza viruses. The FAO said outbreak numbers in 2007 were high between January and April, declined until September, and then started rising again in November and December.

Increased awareness and improved disease surveillance have enabled countries such as India, Romania, Malaysia, and Turkey to detect and control the spread of the H5N1 virus, the FAO reported. However, the disease persists in Asia, Africa, and Europe and poses a risk for countries that have controlled outbreaks in the past and those that have not experienced infections yet, the organization stated.

The FAO said Indonesia is still having a large number of H5N1 outbreaks in poultry, which largely reflects a new "participatory disease search" program designed to detect infections in backyard poultry. The program, with support from the FAO, is operating in 162 districts and nine provinces.

Among other Asian hot spots for the disease, Vietnam reported H5N1 outbreaks in 22 provinces in May, the FAO reported. It said the disease appears to be endemic in Bangladesh.

China had H5N1 outbreaks in Tibet in March, Hunan province in May, and Guangdong province in September, the agency said. In addition, routine surveillance detected the virus in March and April in the southern Chinese provinces of Fujian, Guangdong, Hunan, Hubei, Sichuan, and Chongqing, the FAO reported. Also, wild bird deaths were reported in Hong Kong but not in mainland China.

The only Middle Eastern country reporting an H5N1 outbreak so far this year has been Saudi Arabia, which had its first cases in March, followed by several outbreaks near Riyadh in November.

In Africa, four countries have reported H5N1 outbreaks in 2007, and the FAO said the virus is considered endemic in Egypt and possibly in Nigeria. "Several countries in West, Central, South, and North Africa are at risk of becoming infected, and early warning, surveillance, and preventive measures should urgently be taken," the organization reported.

Eight European countries have reported H5N1 outbreaks in 2007, the FAO noted.